Evidence for CP Violation in B⁺→K*(892)⁺π⁰ from a Dalitz Plot Analysis of B⁺→K[subscript S]⁰π⁺π⁰ Decays

Abstract

We report a Dalitz plot analysis of charmless hadronic decays of charged B mesons to the final state K[subscript S]⁰π⁺π⁰ using the full BABAR data set of 470.9±2.8 million BB[over ¯] events collected at the Υ(4S) resonance. We measure the overall branching fraction and CP asymmetry to be B(B⁺→K⁰π⁺π⁰)=(31.8±1.8±2.1[subscript -0.0][superscript +6.0]×10⁻⁶ and A[subscript CP](B⁺→K⁰π⁺π⁰)=0.07±0.05±0.03[subscript -0.03][superscript +0.02], where the uncertainties are statistical, systematic, and due to the signal model, respectively. This is the first measurement of the branching fraction for B⁺→K⁰π⁺π⁰. We find first evidence of a CP asymmetry in B⁺→K*(892)⁺π⁰ decays: A[subscript CP](B⁺→K*(892)⁺π⁰)=-0.52±0.14±0.04[subscript -0.02][superscript +0.04] The significance of this asymmetry, including systematic and model uncertainties, is 3.4 standard deviations. We also measure the branching fractions and CP asymmetries for three other intermediate decay modes.